Strange Engine Knock

damo2211 · June 15, 2015, 03:01:36 AM

Hi guys I'm new to the forum, i have had my 04 gs500f for 6 months now and it has been a great bike. I have also used this forum and it's very helpfull.
I do need a bit of help to see if any of you have heard this sound before.
I'm pretty sure it came on after i went for a ride into town, i was taking off pretty fast and instead of changing into second it went into neutral and revved right out with a bit of a pop out the exhaust.
There isn't any noticeable power loss but the knocking sound worries me.
The sound does seem to go away after 2000rpm but if you just blip the throttle a bit like i did in the video you can hear it more.
https://www.youtube.com/watch?v=6WJEvbBMsqU

gsJack · June 15, 2015, 05:45:21 AM

Sounds like loose starter clutch to me, I had one last year. Wait for more opinions from younger ears before you start tearing it apart.

The_Paragon · June 15, 2015, 11:03:56 AM

I didnt get to listen the the video... but...

I'd pull the valve cover and see what your valve shims look like... Ehh, maybe one missing?

Its been happening quite a bit lately.

The Buddha · June 15, 2015, 11:13:28 AM

You redline it ?
You may have a loose cam chain (other than the 2 options suggested so far )...
Or you could also have an exhaust leak ...
Or an intake leak ...

Misfires can knock things loose as can an instance of redline ...

Cool.
Buddha.

Atesz792 · June 15, 2015, 12:34:03 PM

I can't hear anything unusual. Would that mean that I might have a problem, too?

W201028 · June 15, 2015, 02:26:19 PM

+1 on the valve shim check. If its starter clutch, that will just get worse until the starter no longer twists the flywheel. Running with a shim out is real damage, real fast. usernamezpd just had this issue last week, and hes in for a new motor.

Maybe this phenomenon needs a nick name like goats. Maybe we call it zpd's?

Supa · June 16, 2015, 06:35:02 AM

Mine sounds a bit similar, but it's an intake leak. I checked the exhaust thinking that was the problem, but it wasn't. A can of carb cleaner and a quick spray around the intake boots threw my idle up by about 300 RPM. Gonna have to tear it down to get back in there and tighten it all up. Last time I checked it, the two bolts holding on the right boot were completely missing and nothing was holding it in place. Replaced those, but I guess it's still not tight enough.

damo2211 · June 16, 2015, 07:13:10 AM

K thanks guys will take the top off on weekend and have a look see what i can find.

The Buddha · June 16, 2015, 09:01:15 AM

That is when you're motor has been K&L'ed ...
Or China shimm'ed.

Cool.
Buddha.

The_Paragon · June 16, 2015, 01:38:52 PM

Quote from: The Buddha on June 16, 2015, 09:01:15 AM
That is when you're motor has been K&L'ed ...

OHH THATS A GOOD ONE!!

Ive been K&L'd!!

Can we submit that one to Merriam-Webster?

damo2211 · June 16, 2015, 02:41:35 PM

what do you mean K&L?

W201028 · June 16, 2015, 02:54:22 PM

Manufacturer of cheaper valve shims; seems to be alot of these shims coming loose from the buckets, or shattering in the buckets, not too sure. I dont think anyone on here has reported finding the whole, mostly intact shim after one of these incidents? Could be comeing apart and then leaving the head

The_Paragon · June 16, 2015, 08:47:02 PM

Yeah the K&L valve shims tend to shatter apart and then come out of the bucket.
In the case of my engine which I replaced 2 shims with K&L brand shims, One shim had shattered apart and resulted in a broken cam chain, and all other associated damages. The other valve shim was soon to do the same as it had cracked in half but was still located in the bucket after the motor destruction.

Ive been working with K&L on this issue... They actually source the shims from an auto parts importer called CRP Automotive, who sources the shims (most likely) from China.

Janx101 · June 16, 2015, 08:52:51 PM

.... go on. .. someone tell me again how cheapo Chinese crappy is just as good?!! ... I love hearing that! .. sure they also produce quality gear when it's to a major customers specs. .. but all the direct knock off stuff is just shitworthy! Shims, led units and assemblies, other electronic things... list goes on. ... sure its cheap! And so much more disposable! ....

Go on! Someone tell me! ... it'll be fun!

gsJack · June 16, 2015, 09:52:59 PM

Quote from: damo2211 on June 15, 2015, 03:01:36 AM.........................The sound does seem to go away after 2000rpm but if you just blip the throttle a bit like i did in the video you can hear it more.
https://www.youtube.com/watch?v=6WJEvbBMsqU

It's hard to imagine a lost shim not being heard at higher rpm's and the engine not having a loss of power without it. Only two knocks I can think of that go away above 2-3k rpm are the camshaft end play knock and the loose starter clutch knock. It's not the cam knock I heard on both my GSs at various times which is at a much lower frequency.

I never heard my loose starter knock above 2-3k rpm. The somewhat common balancer shaft bearing knock and rod and crank bearing knocks are all heard at higher rpm's too. It's good to go ahead and pull the valve cover to check shims and cam chain and tensioner to eliminate the top end. No mention of mileage on this bike but piston slap could be heard at idle and low speeds in a well worn engine.

damo2211 · June 18, 2015, 04:11:05 AM

K bit of an update, took valve cover off, all seems ok so took magneto cover off to inspect starter clutch, seems 2 of the 3 bolts have slightly come undone. I have been trying to undo the main big bolt but cant stop the motor from turning, i dont really want to put anything where the magnets are and damage them.
Is there a trick to undoing that bolt?
Thanks

bmf · June 18, 2015, 04:57:27 AM

I explained my method in a previous post, essentially rear brake with engine in gear and also a chain strap wrench around the rotor. (With rubber strip to protect the rotor)

Sent from my SGH-I337M using Tapatalk

The Buddha · June 18, 2015, 05:40:20 AM

Air impact wrench may get it off. The rotor will need to be pulled off the crank via the use of the almighty sliding hammer.
I made a 30lb behemoth ~10 years ago complete with a 1" handle bar welded to it like clip on's ... loaned it out a couple times and ... well never saw it again.
A 14mm axle off a jap bike FE - like a Vulcan 750 will thread into the rotor, and put a big washer on it and a weight on it before you thread it on. Then slide away.

Cool.
Buddha.

gsJack · June 18, 2015, 05:58:29 AM

Watch Addy's video on pulling rotor:

https://youtu.be/GxS5yZ44AHU

I pulled my rotor using the 14mm bolt and 36mm space method:

http://gstwins.com/gsboard/index.php?topic=67148.msg809633#msg809633

damo2211 · June 19, 2015, 02:28:56 AM

Well the suzuki shop forgot to order the magneto cover gasket so cant get one till next week... sigh.
Wonder if i can get away with gasket goo, it works a treat on cars, any one used it instead of gasket?
http://www.gotstock.com.au/aviation-gasket-sealant-form-a-gasket-50ml-3j-loctiter-no-3.html?gclid=CIP_tYy4m8YCFUKXvQodJYUDgQ

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Strange Engine Knock